<!DOCTYPE html>
<html>
<head>
  <title></title>
</head>
<body>
<div id="app">
  <input type="text" v-model.trim.number="text" @keyup="handleKeyUp">
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.min.js"></script>
<script type="text/javascript">
  let vm = new Vue({
    el: '#app',
    data: () => ({ text: '' }),
    methods: {
      handleKeyUp () {
        console.log(this.text, typeof this.text)
      }
    }
  })
</script>
</body>
</html>